I've never really thought to isolate any one part of the triceps... but the only apparent part of my tris is the lateral head, so maybe my pressing shenanigans will help you:
close grip bench
overhead press
klokovs
handstand pushups
incline bench

I've never really thought to isolate any one part of the triceps... but the only apparent part of my tris is the lateral head, so maybe my pressing shenanigans will help you:
close grip bench
overhead press
klokovs
handstand pushups
incline bench

Also try reverse grip extensions can be a little hard on the wrists so don't over do it but I feel the very hard in the lateral head. Also work on your mind muscle connection I know it sounds kinda retarded but Focus on flexin that part of your tris when lifting and posing in between sets.